How do pods in a service discover each other within a namespace using DNS?

How do pods in a service discover each other within a namespace using DNS?

• A. By the service name (DNS: <service-name>)
• B. By the service cluster IP
• C. By the Deployment name
• D. By the Node name

Answer: (A)

When pods look up other services, they rely on DNS entries that Kubernetes creates for each Service. Within the same namespace, a pod can reach a service simply by using the service’s name. The DNS system resolves that name to the service’s cluster IP, and the service then routes traffic to one of the backend pods that backs the service, providing stable addressing even as individual pod IPs come and go. This is why the service name is the right mechanism: it maps to a stable virtual IP through DNS, enabling reliable inter-pod communication. The cluster IP is the address that DNS resolves to, but you don’t discover others by using the IP directly. Deployment names are controllers, not network endpoints, and Node names refer to machines, not the services you’re trying to reach. If you needed cross-namespace access, you’d use a fully qualified DNS name like service.namespace.svc.cluster.local, but within a namespace the simple service name suffices.

When pods look up other services, they rely on DNS entries that Kubernetes creates for each Service. Within the same namespace, a pod can reach a service simply by using the service’s name. The DNS system resolves that name to the service’s cluster IP, and the service then routes traffic to one of the backend pods that backs the service, providing stable addressing even as individual pod IPs come and go.

This is why the service name is the right mechanism: it maps to a stable virtual IP through DNS, enabling reliable inter-pod communication. The cluster IP is the address that DNS resolves to, but you don’t discover others by using the IP directly. Deployment names are controllers, not network endpoints, and Node names refer to machines, not the services you’re trying to reach. If you needed cross-namespace access, you’d use a fully qualified DNS name like service.namespace.svc.cluster.local, but within a namespace the simple service name suffices.